| 摘要 |
<p>PURPOSE:To allocate a product number to an option board by allocating only an address to a product number reading port by providing the title system with (n)-product number output ports, a binary decoder and a binary counter. CONSTITUTION:The (n) output ports 10-1 to 10-n for outputting product numbers output respective fixed values which are applied to respective inputs when respective signals 107-1 to 107-n are turned to the '0' level to a system data bus 101. Namely, the output of the binary counter 11 having the output of at least [log2(n+1)] to the binary decoder 12 having at least n+1 outputs, the outputs of the decoder 12 are successively connected to the permission signals 107 of the output ports 10 and respective output ports are successively allowed from the 1st one at every activation of a product number reading signal 103. Consequently, a permission number with a variable byte length can be applied to the option board by allocating only an address to the product number reading port.</p> |
